Directions: Read the following text. Choose the best word(s) for each numbered blank and mark A, B, C or D on the ANSWER SHEET. (10 points)
Though not biologically related, friends are as "related" as fourth cousins, sharing about 1% of genes. That is ___1___ a study, published from the University of California and Yale University in the Proceedings of the National Academy of Sciences, has ___2___.
The study is a genome-wide analysis conducted ___3___ 1,932 unique subjects which ___4___ pairs of unrelated friends and unrelated strangers. The same people were used in both ___5___.
While 1% may seem ___6___, it is not so to a geneticist. As James Fowler, professor of medical genetics at UC San Diego, says, "Most people do not even ___7___ their fourth cousins but somehow manage to select as friends the people who ___8___ our kin."
The study ___9___ found that the genes for smell were something shared in friends but not genes for immunity. Why this similarity exists in smell genes is difficult to explain, for now. ___10___, as the team suggests, it draws us to similar environments but there is more ___11___ it. There could be many mechanisms working together that ___12___ us in choosing genetically similar friends ___13___ "functional kinship" of being friends with ___14___ !
One of the remarkable findings of the study was that the similar genes seem to be evolving ___15___ than other genes. Studying this could help ___16___ why human evolution picked pace in the last 30,000 years, with social environment being a major ___17___ factor.
The findings do not simply explain people's ___18___ to befriend those of similar ___19___ backgrounds, say the researchers. Though all the subjects were drawn from a population of European extraction, care was taken to ___20___ that all subjects, friends and strangers, were taken from the same population.
解析形容词辨析题。句意：虽然1%看似微不足道，但对遗传学家来说并非如此。insignificant 意为"微不足道的、不重要的"，与后文"it is not so to a geneticist"（对遗传学家并非如此）形成转折。unexpected"意外的"、unreliable"不可靠的"、incredible"难以置信的"均无法与后文形成合理转折。
解析动词辨析题。句意：……选择与那些像自己亲戚的人做朋友。resemble 意为"与……相似"，呼应前文 friends are as "related" as fourth cousins（朋友与第四代表亲一样"有亲缘关系"）。influence"影响"、favor"偏爱"、surpass"超越"均不符合基因相似性的主题。
解析副词/连接词辨析题。前文说"为何气味基因存在相似性目前难以解释"，后文给出一种推测性解释："正如研究团队所提出的，它可能把我们吸引到相似的环境中……"。Perhaps 表示推测，与 difficult to explain, for now 和后文 as the team suggests 的试探语气一致。Meanwhile"同时"、Furthermore"此外"、Likewise"同样"均过于肯定，与推测语境不符。
11.
A) about
B) to
C) from
D) like
答案 B
解析介词辨析题。there is more to it 是固定表达，意为"事情没那么简单/背后还有更深层的含义"。句意：但事情远不止于此（背后还有更复杂的机制）。about/to/from/like 中，只有 to 能构成此固定搭配。
解析短语辨析题。句意：驱使我们选择基因相似的朋友，而不是"功能上的亲缘关系"所带来的交友好处。rather than 表示"而不是"，对比两种解释：基因相似驱动 vs 功能亲缘关系。according to"根据"、regardless of"不管"、along with"连同"均无法形成此对比。
14.
A) chances
B) responses
C) missions
D) benefits
答案 D
解析名词辨析题。句意：……而不是与朋友交往所带来的"功能亲缘关系"的好处。benefits 意为"好处、益处"，与 functional kinship of being friends with... 搭配，指交友带来的实际利益。chances"机会"、responses"反应"、missions"任务"均不符合"功能亲缘关系"的语义。
15.
A) later
B) slower
C) faster
D) earlier
答案 C
解析副词比较级辨析题。句意：相似基因似乎比其他基因进化得更快。faster 与后文 why human evolution picked pace（人类进化加速）呼应，说明这些基因的进化速度更快，从而帮助解释人类进化的加速。later"更晚"、slower"更慢"（与 picked pace 矛盾）、earlier"更早"均不符合。
解析名词辨析题。句意：这些发现并不能简单地解释人们倾向于与具有相似……背景的人交朋友。tendency 意为"倾向"，与 to befriend 搭配表示"交友倾向"。endeavor"努力"、decision"决定"（过于主动）、arrangement"安排"均不符合"基因层面的倾向性"这一主题。
19.
A) political
B) religious
C) ethnic
D) economic
答案 C
解析形容词辨析题。句意：……与具有相似种族背景的人交朋友。ethnic 意为"种族的、民族的"，与 backgrounds 搭配表示"种族背景"，呼应前文 European extraction（欧洲血统）和基因相似性主题。political"政治的"、religious"宗教的"、economic"经济的"均偏离基因/种族主题。
20.
A) see
B) show
C) prove
D) tell
答案 A
解析动词辨析题。句意：尽管所有受试者都来自欧洲血统人群，但研究人员特别注意确保所有受试者（朋友和陌生人）都来自同一群体。see 在此处意为"确保、留意"（see that... = make sure that...），是正式用语。show"表明"、prove"证明"、tell"告诉"均无法构成 see that 的固定用法。